Dielectric materials has been widely used in a region of a high frequency wave such as a micrometer wave or a millimeter wave. As the characteristics required for the dielectric materials, in particular, small dielectric loss in a high frequency wave region, that is, a high Qf value is required.
As such a dielectric material for use in a high frequency wave, LaAlO3—SrTiO3 dielectric porcelain has been proposed (see, patent document 1). This material can be obtained by calcining oxide powders as raw materials, followed by pulverization, forming and sintering thereof, and the structure thereof is a polycrystalline structure containing a perovskite crystal composed of a LaAlO3—SrTiO3 solid solution as a main phase.
On the other hand, as a material used in a high-temperature superconducting filter for use in high frequency wave and so on, MgO single crystal and LaAlO3 single crystal has been known (see, non-patent document 1).
Patent document 1: JP-A-11-71171
Non-patent document 1: MWE 2000 Microwave Workshop Digest 337-340 “High Temperature Supersonducting Filer for Wireless Base Station”